Internal combustion engine



'March 16, 11.937.v GMHCKNELL Y 2,073,620 y INTERNAL COMBUST ION ENGINE Filed June 17, 1929 v12 Sheets-Sheet l @.MBickwel March 16, 1937 G. M. BICKNELL INTERNAL COMBUST ION ENGINE 2 Sheets-Sheet 2 Filed June 17, 1929 Patented Mar. 16, 1.931

mrnnNAL coMBUs'rioN nNGrNE George M. Bicknell, st. Louis, Mo., assis-'nor tol- Waukesha Motor Company Waukesha, Wis., a

corporation of Wisconsin Application June 1r, 1929, serial Nofa'zlsu Y 2 Claims.

ternal combustin engines and particularly .to the provision of a combustion chamber of an 'improved design-and lalso to valve'cooling arrange- 5 ments for such engines." l Heretofore, dilculty has been experienced inA engines of thisnature due to preignition 'and' detonation of the fuel charge. I have found that this diiiiculty can be remedied to a great extent by concentrating the -maln volume of ,the fuel charge at the time of combustion in a ipart .of the combustion chamber which is comparatively/cool. Exhaust valves of the usual poppet type have practically their whole surface exposed directly 1,15 tosthe llame during the exhaust cycle, and since the only paths of escape for 'the heat are through .the seat and stem ofthe valve, the heads of these valves sometimes become unduly hot or even incandescent, -resulting in deterioration of the metal and preignition and detonation of the 1 charge.

It is an object of this invention to produce a combustion chamber for internal combustion engines in which the main part of the volume will be concentrated in a part of the chamber which is comparatively coolin other words,-to concentrate the volume ofthe combustion chamber adjacent the coolest parts of its walls. It will be understood, of course, that the walls of the chamber include the heads of the inlet and ex' haust valves as well as 'the top of the piston.

Itl is a further object of this invention to pro. duce an engine having valves of the poppet type and of such construction and arrangement that a minimum `portion of thesurface of the valve will be exposed to the ame of the exhaust. Other objects of .the invention will appear from the following specication and the accompanying drawings, referring to which:

Figure 1 is a sectional plan view of an engine constructed in accordance with my invention taken along the line I--I of Figure 2. v

Figure 2 is a sectional elevationltaken along the line 2--2 of Figure 1.

Figure 3 is a sectional elevation taken along thV line 3 3 ofFigure 1.

Flgurei is a sectional elevation taken along the line 4-4 of Figure 1. j

Figure 5 is a' sectional elevation taken along the line'S--ii of Figure 1.

For convenience of illustration, an engine having a single cylinder has been shown. It will be obvious that the invention is applicable to engines having any number of cylinders.

The reference numeral l indicates an inter/nal t y. l (cries-191) This-invention relates to improvements in in- `combustion eng-ine cylinder havinga head -2 and a combustion chamber generally indicated at 3.

The cylinder is provided with the usual water jacket 4' and the head is also jacketed to contain a cooling vnid'as indicated' at I5. 5

Inlet and exhaust valves 5 and 6, respectively,`

of the conventional poppet type are provided.' A

conventional piston 1 operates in the cylinder I.

TheA formation of the piston chamber in the cylinder head is such that'a greaterVA part of the 10 volume of the combustion chamber is adjacent the inlet valve than in prior constructions. An upwardly extending portion of the 'combustion chamber, as indicated, at 8 is locatedl adjacent the inlet valve. 16 -This portion of the chamber is arranged to con# tain the greater part of the volume, and the wall of the chamber is so formed as to leave only a comparatively thin layer of gas between the greater part `of the the chamber.'

l i'l'hat portion of the wall of the combustion chamber which isv over the exhaust valve is so formed that when the exhaust valve is open, there will be only a very small clearance between the top 2 5 of the valveand the top of the combustion chamber. Some clearance is, ofcourse, necessary forv tolerance vin manufacturing and operation, but `the space is so reduced, as indicated at 9, that there will be substantially no flow of flaming A30 gas over the top of the exhaust valve during the exhaust cycle. The proximity of the top of th'e exhaust valve to the water cooled surface of the combustion chamber results in a more eflicient cooling of the valve, and at the same time the- 35 valve protects a part of the `Wall of the combustion` chamber from the flame, resulting in a cooler operating motor generally..

.The reduction of volume of the combustion( chamber at the point above the exhaust valve' 40 and above the greater part of the piston head resuits in the reduction of volume at all points except adjacent the inlet valve which is comparatively cool in operation Vdue to the passage through it of the cool fuelgas. tion results in a number This construc- 45 of advantages, some of which are as follows:

The reduction in the thickness of the layer of fuel directly above the piston results in the trans- -mission of less heat to the piston during that part 50 of the cycle. in which vthe piston is at the top of its stroke, and the proximity of the top of the piston to the cooled wall dof. the cylinder head results in the comparatively free transmission of heat away from the piston top. The piston be- 55 piston head and the wall of 20 ing rather diiiicult to cool effectively is, in any case, likely to get very hot and cause detonation, and this reduction in the amount of heat transmitted to it results in lower operating temperatures and less likelihood of detonation as well as in leaving a smaller amount of gas subject to the detonation in case it should occur under extreme operating conditions. The reduction in volume of the combustion chamber adjacent theexhaust .10 valve also has the same advantages.-

In modern automobile engine construction,` itv is customary to make a plurality of the cylinders in a single block and to have the water jacket of the head of a substantially ilat and rectangular 15 construction, that is to say, the outer wall of the water jacket usually lies in a plane substantially perpendicular to the axis of the cylinder. By enlarging the space above the inlet valve, I have reduced the thickness of the water jacket, as in- 20 dicated at I0. This portion-of the combustion chamber being normally cooled to a considerable4 extent by the cool -fuel from the inlet manifold does not in any case become as hot as other portions of the combustion chamber. At the same time, the spark plug H does not have to pass so far through the water jacket, and a comparatively short plug may be used.

The reduction in volume of the combustion 3o chamber at the point above the exhaust valve results in a maximum thickness of the Water jacket at that point, as indicated at lla, thereby giving a large volume of water or other cooling uid at this point, which requires more cooling than any 35 other portion of the combustion chamber.

In operation, the valves 5 and 6 and the piston 'I arereciprocated by conventional means (not shown) in such a manner as to produce the wellknown four-cycle operation. Near the end of the 40 power stroke, the exhaust valve B is opened to such a position that its head is in proximity to the wall 2 of the combustion chamber, as indicated at 9. Such portions of the exhaust gas as come into contact with the exhaust valve at all during this portion of the cycle come in contact only with the stem and the under surface of the head of the valve. There is, of course, some gas in contact .with the upper surface of the valve, but it is a thin layer, flowing at a comparatively slow rate, so that-the heat transmitting eiiect is less. The heat taken up by the lower` surface and stem of the exhaust valve is conducted down the stem of the valve from which it may be dissipated by the action of the water jacket I.

I claim:

1. In an internal combustion engine of the L- head type, a combustion chamber having inlet and exhaust valves opening into the said chamber, said chamber having a portion of great depth adjacent the inlet valve and a portion of less depth adjacent the exhaust valve, said por-v tions of the combustion chamber being in direct communication, said chamber having a third portion of less depth than that portion adjacent the exhaust valve, said third portion being directly adjacent the piston of the engine when it is at the top of its stroke, the cylinder roof overlying said third portion being inclined upward toward and merging into the roof of said rst portion and the roof of said second portion,` the roof of said second portion being inclined upward toward said first portion and merging into the adjacent Wall of the latter.

2. In an internal combustion engine of the L-head type, a cylinder and a piston operating therein, a combustion chamber lying to one side of and opening into said cylinder, inlet and exhaust valves arranged side by side in said chamber, the latter defining a relatively shallow pocket over the exhaust valve and a. relatively high pocket over the inlet valve, said pockets opening freely one into the other, and a spark plug mounted in the roof of said relatively high pocket in alignment with and overlying said inlet valve.

GEORGE M. BICKNELL. 

